The proposed program will deal with: A. The uncoupling activity of colicins of the K and E1 group and of bacterial mutations that mimic in some way colicin action. The membrane proteins involved will be identified by means of uncoupled amber mutants. The interaction of such proteins with colicins will be explored by physical chemical methods. The proximate goal is to clarify the role of any such proteins as coupling factors between membrane energy (presumably proton-motive force) and various active transport systems. B. The overall regulation of genetic transcription of the initiation level in E. coli will be explored following our discovery of the key role of adenylate kinase in this regulation. We shall try to identify the primary regulatory substance (possibly an AMP derivative) and to relate its effects to the known roles of adenylate change in metabolism. BIBLIOGRAPHIC REFERENCES: Luria, S.E.: Colicins and the Energetics of Cell Membranes. Scientific American 233:30-37, (1975). Luria, S.E., Suit, J.L., and Plate, C.A.: Initiation of Transcription is Temperature-dependent in an E. coli Mutant with ts Adenylate Kinase. BBRC 67:353-358, (1975).